What is Spin? Spin is a general tool for the specification and formal verification of software for distributed systems. It has been used to detect design errors in a wide range of applications, such as abstract distributed algorithms, data communications protocols, operating systems code, and telephone switching code. The verifier can check for basic correctness properties, such as absence of deadlock and race conditions, logical completeness, or unwarranted assumptions about the relative speeds of correctness properties expressed in the syntax of Linear-time Temporal Logic (LTL). The tool translates LTL formulae automatically into automata representations, which can be used in an efficient on-the-fly verifications procedure.This DIMACS volume presents the papers contributed to the second international workshop that was held on the Spin verification system at Rutgers University in August 1996. The work covers theoretical and foundational studies of formal verification, empirical studies of the effectiveness of different types of algorithms, significant practical applications of the Spin verifier, and discussions of extensions and revisions of the basic code.